/*
 * Copyright (C) 2007 The Guava Authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.common.collect.testing.testers;

import static com.google.common.collect.testing.features.CollectionFeature.KNOWN_ORDER;
import static com.google.common.collect.testing.features.CollectionSize.ZERO;

import com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.GwtIncompatible;
import com.google.common.collect.testing.AbstractCollectionTester;
import com.google.common.collect.testing.Helpers;
import com.google.common.collect.testing.WrongType;
import com.google.common.collect.testing.features.CollectionFeature;
import com.google.common.collect.testing.features.CollectionSize;

import java.lang.reflect.Method;
import java.util.Arrays;
import java.util.Collection;
import java.util.List;

import org.junit.Ignore;

/**
 * A generic JUnit test which tests {@code toArray()} operations on a collection. Can't be invoked
 * directly; please see {@link com.google.common.collect.testing.CollectionTestSuiteBuilder}.
 *
 * @author Kevin Bourrillion
 * @author Chris Povirk
 */
@GwtCompatible(emulated = true)
@Ignore // Affects only Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.
public class CollectionToArrayTester<E> extends AbstractCollectionTester<E>
{
    public void testToArray_noArgs()
    {
        Object[] array = collection.toArray();
        expectArrayContentsAnyOrder(createSamplesArray(), array);
    }

    /**
     * {@link Collection#toArray(Object[])} says: "Note that {@code toArray(new Object[0])} is
     * identical in function to {@code toArray()}."
     *
     * <p>For maximum effect, the collection under test should be created from an element array of a
     * type other than {@code Object[]}.
     */
    public void testToArray_isPlainObjectArray()
    {
        Object[] array = collection.toArray();
        assertEquals(Object[].class, array.getClass());
    }

    public void testToArray_emptyArray()
    {
        E[] empty = getSubjectGenerator().createArray(0);
        E[] array = collection.toArray(empty);
        assertEquals(
                "toArray(emptyT[]) should return an array of type T", empty.getClass(), array.getClass());
        assertEquals("toArray(emptyT[]).length:", getNumElements(), array.length);
        expectArrayContentsAnyOrder(createSamplesArray(), array);
    }

    @CollectionFeature.Require(KNOWN_ORDER)
    public void testToArray_emptyArray_ordered()
    {
        E[] empty = getSubjectGenerator().createArray(0);
        E[] array = collection.toArray(empty);
        assertEquals(
                "toArray(emptyT[]) should return an array of type T", empty.getClass(), array.getClass());
        assertEquals("toArray(emptyT[]).length:", getNumElements(), array.length);
        expectArrayContentsInOrder(getOrderedElements(), array);
    }

    public void testToArray_emptyArrayOfObject()
    {
        Object[] in = new Object[0];
        Object[] array = collection.toArray(in);
        assertEquals(
                "toArray(emptyObject[]) should return an array of type Object",
                Object[].class,
                array.getClass());
        assertEquals("toArray(emptyObject[]).length", getNumElements(), array.length);
        expectArrayContentsAnyOrder(createSamplesArray(), array);
    }

    public void testToArray_rightSizedArray()
    {
        E[] array = getSubjectGenerator().createArray(getNumElements());
        assertSame(
                "toArray(sameSizeE[]) should return the given array", array, collection.toArray(array));
        expectArrayContentsAnyOrder(createSamplesArray(), array);
    }

    @CollectionFeature.Require(KNOWN_ORDER)
    public void testToArray_rightSizedArray_ordered()
    {
        E[] array = getSubjectGenerator().createArray(getNumElements());
        assertSame(
                "toArray(sameSizeE[]) should return the given array", array, collection.toArray(array));
        expectArrayContentsInOrder(getOrderedElements(), array);
    }

    public void testToArray_rightSizedArrayOfObject()
    {
        Object[] array = new Object[getNumElements()];
        assertSame(
                "toArray(sameSizeObject[]) should return the given array",
                array,
                collection.toArray(array));
        expectArrayContentsAnyOrder(createSamplesArray(), array);
    }

    @CollectionFeature.Require(KNOWN_ORDER)
    public void testToArray_rightSizedArrayOfObject_ordered()
    {
        Object[] array = new Object[getNumElements()];
        assertSame(
                "toArray(sameSizeObject[]) should return the given array",
                array,
                collection.toArray(array));
        expectArrayContentsInOrder(getOrderedElements(), array);
    }

    public void testToArray_oversizedArray()
    {
        E[] array = getSubjectGenerator().createArray(getNumElements() + 2);
        array[getNumElements()] = e3();
        array[getNumElements() + 1] = e3();
        assertSame(
                "toArray(overSizedE[]) should return the given array", array, collection.toArray(array));

        List<E> subArray = Arrays.asList(array).subList(0, getNumElements());
        E[] expectedSubArray = createSamplesArray();
        for (int i = 0; i < getNumElements(); i++)
        {
            assertTrue(
                    "toArray(overSizedE[]) should contain element " + expectedSubArray[i],
                    subArray.contains(expectedSubArray[i]));
        }
        assertNull(
                "The array element immediately following the end of the collection should be nulled",
                array[getNumElements()]);
        // array[getNumElements() + 1] might or might not have been nulled
    }

    @CollectionFeature.Require(KNOWN_ORDER)
    public void testToArray_oversizedArray_ordered()
    {
        E[] array = getSubjectGenerator().createArray(getNumElements() + 2);
        array[getNumElements()] = e3();
        array[getNumElements() + 1] = e3();
        assertSame(
                "toArray(overSizedE[]) should return the given array", array, collection.toArray(array));

        List<E> expected = getOrderedElements();
        for (int i = 0; i < getNumElements(); i++)
        {
            assertEquals(expected.get(i), array[i]);
        }
        assertNull(
                "The array element immediately following the end of the collection should be nulled",
                array[getNumElements()]);
        // array[getNumElements() + 1] might or might not have been nulled
    }

    @CollectionSize.Require(absent = ZERO)
    public void testToArray_emptyArrayOfWrongTypeForNonEmptyCollection()
    {
        try
        {
            WrongType[] array = new WrongType[0];
            collection.toArray(array);
            fail("toArray(notAssignableTo[]) should throw");
        }
        catch (ArrayStoreException expected)
        {
        }
    }

    @CollectionSize.Require(ZERO)
    public void testToArray_emptyArrayOfWrongTypeForEmptyCollection()
    {
        WrongType[] array = new WrongType[0];
        assertSame(
                "toArray(sameSizeNotAssignableTo[]) should return the given array",
                array,
                collection.toArray(array));
    }

    private void expectArrayContentsAnyOrder(Object[] expected, Object[] actual)
    {
        Helpers.assertEqualIgnoringOrder(Arrays.asList(expected), Arrays.asList(actual));
    }

    private void expectArrayContentsInOrder(List<E> expected, Object[] actual)
    {
        assertEquals("toArray() ordered contents: ", expected, Arrays.asList(actual));
    }

    /**
     * Returns the {@link Method} instance for {@link #testToArray_isPlainObjectArray()} so that tests
     * of {@link Arrays#asList(Object[])} can suppress it with {@code
     * FeatureSpecificTestSuiteBuilder.suppressing()} until <a
     * href="http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6260652">Sun bug 6260652</a> is fixed.
     */
    @GwtIncompatible // reflection
    public static Method getToArrayIsPlainObjectArrayMethod()
    {
        return Helpers.getMethod(CollectionToArrayTester.class, "testToArray_isPlainObjectArray");
    }
}
